All of a sudden my HP Color Laser M750 will not print black, I cleaned it and put in a new toner.

[sph346]

My HP 750 has been working just fine until I cleaned it and put in a new toner cartridge.  Now the color prints just fine just not the black.  I tried again with a new black toner but still no luck.  It is like something got switched off all of a sudden.

[Repairatrooper · Accepted solution]

Issues we have seen before include the shutter lever in the door getting dislodged and the main drum contact getting bent. When you open the front door there should be 4 identical black toggles. These open the laser shutters when the doors are closed. The contact is at the top of the cartridge cavity,  again all four cartridge slots should be identical.

[sph346]

I have look very close to the configuration of each cartridge location and the slots and they all look to be identical and working the same.  I see the small wire contact at the top but I have not identified a black toggle.  I am wondering if the small wire contact might be the problem having become disconnected.  Let me know what you think.  And! thank you for your response.